Replacing leisure batteries with Lithium batteries

[BEN TAYLOR]

I have recently been recommended lithium batteries as replacements for the original leisure batteries. Half the weight, twice the capacity I am told. And twice the price from what I can see. I am inclined to think the weight savings and potential gains are unnecessary. And a bit of background reading suggests potential charging challenges, depending on setup. But I would be interested to hear your thoughts on these:

http://www.powerxtreme.nl/en/

 

[AlanC]

Yes, Li-on batteries are more expensive and much lighter that lead acid batteries.

The most important thing to know is that the charger fitted to your van is a simple constant voltage type which is designed specifically for lead acid batteries. The charge voltage stays constant and as the battery charges up the current drawn by the battery reduces.

The mains charger also trickle charges the engine battery when on hook up. That needs to stay as a lead acid battery as this is the only type that can take the deep drain starting the engine produces, and then needs to be immediately recharged, which the alternator will do when the engine is running.

The alternator is also used to trickle charge the leisure batteries when the engine battery is fully charged.

A Li-on battery requires a more complex charger which combines constant current with constant voltage and can't be used for a lead acid battery.

The bottom line is you cannot just change the batteries for a different type without changing the charger too and disconnecting the engine battery and alternator charging system from the leisure batteries.

Alan

 

[Sp0_0k]

Plan to add an extra leisure battery but Lifepo4 as more safer and stable one.
Did lots of wild camping our last 100 days trip and want to add like 150-200AH to safely use 2 freezers and laptop non stop for 2-3 days.
Got a question though where do I get the power from the alternator. I had that option ticked when buying, was called something like interface for the extra hardware.
Getting power directly from the alternator I can make it charge faster than messing with the cig lighter socket.
P.S. might not be even worth it messing with the hookup charger.
Anybody got info on that "interface", please?

 

[Loz]

I echo what Alan says above, you will need to change the factory fitted split charge to a DC-DC charger compatible with a Li-on charging profile. I would also disconnect the factory battery charger from the leisure side and perhaps swap it to the starter battery and provide a new mains charger for the leisure batteries.

 

[Max-Felix]

I'd just spend £300 on a simple full time BT app based solar set up and stick with the factory batteries. I've posted before (more than once! ) that solar is one of the best no-brainer happy-making budget options you can fit to a Cali but I won't go on about it again...

 

[Sp0_0k]

I'd just spend £300 on a simple full time BT app based solar set up and stick with the factory batteries. I've posted before (more than once! ) that solar is one of the best no-brainer happy-making budget options you can fit to a Cali but I won't go on about it again...

Tons of sun up North this trip. Especially in Autumn. I would be getting like 20-40watt max from 200w combined pannels?
2kwh battery and alternator doesn't add that much on consumption charging that.
I don't want to increase the vehicle height even a centimeter as well.

 

[Sp0_0k]

And twice the price from what I can see.

Lifepo4 can easily outlast the whole vehicle life though with more than 2k full charge cycles.

 

[mackem10000000]

I echo what Alan says above, you will need to change the factory fitted split charge to a DC-DC charger compatible with a Li-on charging profile. I would also disconnect the factory battery charger from the leisure side and perhaps swap it to the starter battery and provide a new mains charger for the leisure batteries.

Looking to do the same myself, but bit confused. If I take out the split charge relay and fit dc-dc charger, would the charger not be running constantly and flatten the starter battery?......could the split charge relay be left in so engine charging only happens when engine is running....Any advice much appreciated

 

[Sp0_0k]

Many DC-DC chargers have input voltage detection. So lets say when above 13v it charges. Car battery drops to 12,8v when engine stops. Just a little issue idle consumption. If you leave it for a month with engine off it might flatten car battery.

 

[mackem10000000]

Many DC-DC chargers have input voltage detection. So lets say when above 13v it charges. Car battery drops to 12,8v when engine stops. Just a little issue idle consumption. If you leave it for a month with engine off it might flatten car battery.

Dooohh, didn't think of that. Thanks Sp.....I've just ordered one of them Victron Orion chargers, so hopefully that will do input voltage sensing. Hope so, the price of it.

 

[Sp0_0k]

I wasn't happy with Victron one. Had 18amps, has only passive cooling, so was overheating a lot even with added cooler. And it never did full amps. Found 40amp one that even has built in solar input, and most importantly can adjust from 5 to 40 amps. For some reason victron can't do that.

 

[Sp0_0k]

I use this one right now and very happy. Cheapest of all available options on the market.
Carspa PBC1212-40

 

[mackem10000000]

Interesting....I like the way it has multiple inputs.....Are you using it with lifepo4? Did you have to change the settings

 

[Sp0_0k]

Yes, built several lifepo4 myself. 4kwh + 1,5 kwh using right now.
That Carspa model has extra remote sold for it so settings are very easy to adjust.
There is no need to change much for lifepo4.
Battery with BMS can accept any CC CV charge. So you can use even old DC chargers for lead batteries. I limit top voltage in bms at 13,8v anyway to keep them healthy.

Btw I still use one original AGM 80ah leisure battery just in case and like how original VW direct connection charges it very fast at up to 80amps.
Just added 2 lifepos extra. So over 7kwh total leisure on board now

 

[mackem10000000]

Wow, a power station on wheels....Are you in the mobile rave business by any chance......Yea, I used to think all lithium batteries needed special chargers, but now realising lifepo4 can be charged with almost anything, guess the only thing is protecting the alternator from burning itself out.

 

[Sp0_0k]

We just use full electrics. Cooking, drying, 2 fridges, 2 computers. Gas is too messy for cooking.
And we live in a van for 2-3 months in the North.

 

[mackem10000000]

Another question though. My lifepo4 battery is a bit tall for the leisure battery compartment under wardrobe. Looking at the manufacturer details it says it can be used on its side or even upside down. Has anyone ever tried this?

 

[Sp0_0k]

Another question though. My lifepo4 battery is a bit tall for the leisure battery compartment under wardrobe. Looking at the manufacturer details it says it can be used on its side or even upside down. Has anyone ever tried this?

Highly not recommended on the side.
280ah cells are pretty low, so can custom build bms on the side with battery hight 22cm max.
I custom built very high but very narrow perfectly for beach storage box.
Most retail built lifepo4 use bigger plastic casing with empty space wasted inside.

 

[Wannabecamperman]

Lifepo4 can easily outlast the whole vehicle life though with more than 2k full charge cycles.

Actually mine has a 3000 cycle warranty to 80%. LiFePO4 all the way.

 

[mackem10000000]

Thanks for that, will take a look inside the case, does feel like there's not much in there.....So how far North are we talking. North of Scotland?